Elon Musk was at the AllThingsD D11 conference yesterday, and talked a big transport game. As well as an announcement that there would be a huge increase in charging posts for the entrepreneur’s Tesla vehicles, he teased the audience with news of his Hyperloop transport system, which plans to link San Francisco with Los Angeles, a distance of almost 400 miles.

The proposed superfast train link (which, Musk pointed out, would be the slowest superfast train link in the world) was a non-starter. Instead, said Mr. SpaceX, his Hyperloop would be “a cross between a Concorde, a rail gun, and an air hockey table.” Maybe it would have solar panels on it, maybe it would complete the journey in around half an hour. More details would emerge next month, he said.